A fiber laser is utilized as a laser that is used in cuffing and piercing processing and surface printing (marking) of metal and plastic and the like. Patent Document 1 discloses in detail a method of using such a fiber laser.
FIG. 5 is a drawing that shows the basic construction of the fiber laser disclosed in Patent Document 1. This fiber laser multiplexes light of a signal light source Is (pulsed light) and a pumping light source Ps (CW light) with a BS and inputs each to a rare earth-doped double clad fiber 1, and as a result a high power pulsed amplified light with an output pulse peak power of several hundred to several MW is obtained.
Also, Patent Document 2 discloses in detail a method of using Stokes light of stimulated Raman scattering by pulsed light. FIG. 6 is a block diagram that shows an optical pulse generator 2 that uses Stokes light of Raman scattering described in Patent Document 2. This optical pulse generator 2 inputs pulsed light of 1 kW that is output from a 1.32 μm wavelength Nd:YAG laser 3 into an optical fiber 4 with a length of 1.7 km, takes out with a spectrometer 5 only the second Stokes light (wavelength of 1.49 μm) among the generated Stokes lights (refer to FIG. 7), and obtains an output of approximately 1 W.    [Patent Document 1] Japanese Patent, Publication No. 3567233    [Patent Document 2] Japanese Unexamined Patent Application, First Publication No. S58-70140    [Patent Document 3] Japanese Patent, Publication No. 2753539    [Non-Patent Document 1] G. Bouwmans, “Fabrication and characterization of an all solid 2D photonic bandgap fiber with a low loss region (<20 dB/km) around 1550 nm”, OPTICS EXPRESS 17, Vol. 13, No. 21, 2005, pp 8,452-8,459.